Fan heater unit



March 10, 1942. c, O BERGSTROM 2,276,144

FAN HEATER UNIT Filed Aug. 17, 1940 fawezaior: CawZ aflewgsi 'wom 9 a. w

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Patented Mar. 10, 1942 FAN HEATER, UNIT Carl 0. Bergstrom, Boston,Mass., assignor to B. F. Sturtevant Company, Boston, Mass.

Application August 17, 1940, Serial No. 352,987

1 Claim.

This invention relates to fan-heater units and relates more particularlyto a combined centrifugal fan and electric air heater.

Electric heaters combined with fans have been proposed heretofore but sofar as is known, such prior devices have been mere auxiliary heaters andwere not capable of high duty performance. The present invention wasdeveloped for electric subway passengers cars which formerly used floortype heaters and overhead air circulating fans, and provides in overheadfan-heater units, equipment which provides more even and eflicientheating and more adequate air circulation than the prior equipment wascapable of.

The prior combined electric heater and [an units utilized heater wiresarranged around the fan outlet or between same and the space served.Such arrangements while suitable for auxiliary heater units were notfeasible for heating passenger cars due to the difiiculty of circulatingthe heated air and of protecting the'equipment from the heat.

The present invention utilizes electric heater elements mounted withinthe wheel of a centrifugal fan rather than at the fan outlet as has beenthe practice in the past. The heater elements are nearest the fan bladeswhich are in motion and are not damaged by the tremendous heat developedand which force the heated air through the other elements of the fan atreduced 3 temperatm. The air is evenly heated due to the circulararrangement of the heater elements around the circular opening withinthe fan wheel.

An object of the invention is to provide an improved fan-heater unitcapable of providing and circulating very hot air.

The invention will now be described with reference to the drawing, ofwhich:

Fig. 1 is a plan view looking downwardly upon a fan-heater unitembodying this invention;

Fig. 2 is an elevational view of the unit of Fig. 1, with a portion insection, and

Fig. 3 is a view similar to Fig. 2 but taken along the lines 33 of Fig.2.

The fanconsists of the air guiding inlet casing 5, attached at fourpoints by the bolts 8 and nuts I to the plate 8 which is attached arounda circular opening to the roof 9 of the car. The bolts 8 also supportthe horizontal, air diffuser plates 10. The fan wheel consists of theback plate I l, the side plate It, the blades l3, and the shaft supportI attached to the back plate and rotated by the electric motor [5. Themotor I! is sup ported from the casing I! by the arms ll.

The resistor clamps ll are attached to the inlet portions of the casingI2 and extend within the fan wheel between the blades l3 and support theresistors 18, of which there are two, each extending substantiallycompletely around the inside of the fan wheel in a circular path.

The upper resistor 18 has the two extensions I!) which form the leads orconnections for electric supply. The lower resistor l8 has the twosimilar extensions 20 serving as supply leads. With the leads broughtout as illustrated, the two resistors 18 may be connected separately tothe electric supply, or in series or in parallel to provide differentdegrees of heat. The resistors [8 in one embodiment of the inventionwere formed from calrod wire and when connected in parallel to a 600volt electric supply consumed 3 kilowatts of energy, and throughoperation of the fan, the resulting heat was distributed evenly andwithout injury to the fan due to the location of the resistors withinthe fan wheel.

While one embodiment of the invention has been described for the purposeof illustration, it should be understood that the invention is notlimited to the exact apparatus and arrangement of apparatus illustratedas modifications thereof may be suggested by those skilled in the artagithout departure from the essence of the invent on.

What is claimed is:

A fan heater unit for mounting to a surface comprising a plate having acentral opening therein for the passage of air, means attached to oneside of said plate around said opening and forming supports forattaching said unit to said surface, a centrifugal fan, means forattaching said fan to the other side of said plate, said fan including afan wheel having a back plate and having a central inlet opening inaxial alignment with said opening in said plate, an inlet casing havingan outer end extending from said plate around the openingthereiri andhaving an inner end extending into said inlet opening, a plurality ofspaced air diffusing plates extending around said wheel perpendicular tothe axis thereof, and an electric resistor element supported within saidinlet opening between said inner end of said casing and said back plateextending in a circular are substantially around the circumferencethereof.

CARL o. BEltGSTROM.

